orbitolite|ɔːˈbɪtəlaɪt| [In mod.L. orbitolītēs, f.orbita orbit n. + Gr. λίθος stone: see -lite.] a. The fossil shell of a Foraminifer of the genus Orbitolites. b. A fossil coral of the genus Orbitolites or Chætites. 1865Carpenter in Intell. ObserverNo. 40. 297 Internal casts of an Orbitolite.